Are Protons Magnets? Investigating Spin & Charge

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Discussion Overview

The discussion explores whether protons can be considered magnets due to their spin and charge, comparing them to electrons. Participants investigate the implications of magnetic moments, the orientation of magnetic poles, and the magnetic fields produced by these particles.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants assert that protons, like electrons, have spin and charge, suggesting they function as magnets with distinct north and south poles.
  • Others explain that protons and neutrons exhibit magnetic moments due to their internal quarks, despite neutrons having no charge.
  • There is a question about the orientation of the magnetic poles when viewed from a specific angle, leading to discussions about the relationship between spin and magnetic moment direction.
  • Some participants clarify that the magnetic moment of the proton aligns with its spin, while the electron's magnetic moment opposes its spin due to its negative charge.
  • Participants discuss the concept of "top" in the context of magnetic orientation, referencing the right-hand rule for rotation.
  • There is a comparison made between the Earth and electrons regarding magnetic pole orientation, leading to questions about the strength of magnetic fields produced by individual electrons and protons.
  • Some participants provide estimates for the magnetic field strength of protons and electrons at specific distances, noting the differences in their magnitudes.

Areas of Agreement / Disagreement

Participants generally agree that protons can be considered magnets due to their magnetic moments, but there are competing views on the specifics of their magnetic properties and the calculations involved. The discussion remains unresolved regarding the exact magnetic field strengths of lone protons and electrons.

Contextual Notes

Participants mention various assumptions regarding the calculations of magnetic fields, including distance dependencies and the nature of magnetic moments. The discussion does not resolve how these factors influence the overall understanding of magnetic properties.

davidong3000
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i know electrons have spin and charge which makes them the smallest magnet. protons also have spin and charge. does this mean they are magnets too with a north and south pole?

Precisely where are these poles in relation to the spin axis of the proton and electron?
 
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davidong3000 said:
i know electrons have spin and charge which makes them the smallest magnet. protons also have spin and charge. does this mean they are magnets too with a north and south pole?

Precisely where are these poles in relation to the spin axis of the proton and electron?


Yes, protons are magnets, and they precess. So do neutrons oddly enough. In spite of having no charge, they have a magnetic moment, due to the charged and spinning quarks inside them (the quarks' charges cancel out in the neutron, but add in the proton). These facts are behind the chemistry analytical tool NMR, for nuclear magnetic resonance, and that in turn is behind the medical device MRI, magnetic resonance imaging.
 
so if i was looking down on the axis of an electron/proton in such a way so that it appears to be spinning anti clockwise, would i be looking at the north or south pole?
 
davidong3000 said:
so if i was looking down on the axis of an electron/proton in such a way so that it appears to be spinning anti clockwise, would i be looking at the north or south pole?
The magnetic moment of the proton is in the same direction as its spin, so its N pole would be on top. The electron magnetic moment is oppositeto its spin direction because the electron is negatively charged.
Its top pole is a S pole.
Note, even though these particles have "spin", they are not rotating.
They are said to have spin because they have angular momentum.
This follows from relativistic QM (the Dirac equation) without their actually rotating.
 
Meir Achuz said:
The magnetic moment of the proton is in the same direction as its spin, so its N pole would be on top. The electron magnetic moment is oppositeto its spin direction because the electron is negatively charged.
Its top pole is a S pole.

Can u define "top"?
 
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The north pole would be at the "top" of the earth.
By "top" I meant where the head of the arrow woud be in the right hand rule for rotation. (If fingers curl in direction of rotation, the vector omega is in the direction of the thumb.)
 
Meir Achuz said:
The north pole would be at the "top" of the earth.
By "top" I meant where the head of the arrow woud be in the right hand rule for rotation. (If fingers curl in direction of rotation, the vector omega is in the direction of the thumb.)

And actually the magnetic "pole" of the Earth on the north pole is ...
a magnetic south pole !
 
vanesch said:
And actually the magnetic "pole" of the Earth on the north pole is ...
a magnetic south pole !

so Earth is like a giant electron then . xcept Earth is not - charged. both Earth and electrons have their s pole on top according to rh rule.

so exactly how many teslas are single electrons and protons spitting out? and do the magnetic fields of these charged particles loop back on themselves from top to bottom like on ordinary magnets?
 
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davidong3000 said:
so Earth is like a giant electron then . xcept Earth is not - charged. both Earth and electrons have their s pole on top according to rh rule.

so exactly how many teslas are single electrons and protons spitting out? and do the magnetic fields of these charged particles loop back on themselves from top to bottom like on ordinary magnets?
The second answer is yes.
The first answer is a bit messy to calculate, but I get that the B field at the proton in hydrogen due to the electron's magnetic moment is about
one million tesla.
 
  • #10
Meir Achuz said:
The second answer is yes.
The first answer is a bit messy to calculate, but I get that the B field at the proton in hydrogen due to the electron's magnetic moment is about
one million tesla.

what if it didn't have an electron? say a lone proton or lone electron, what would the tesla reading be?
 
  • #11
davidong3000 said:
what if it didn't have an electron? say a lone proton or lone electron, what would the tesla reading be?
I used the H atom just as an example for the B field a distance of 1/2 angstrom away from a lone electron. The B field would fall of like 1/r^3, so an electron's B field would be about 100,000 T 1 angstrom away.
The B field of a proton would be about 600 times smaller than that of an electron at the same disstance.
 

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